1. Field of the Invention
The present invention relates to a puncture device with a flexible catheter tube for connecting to a medical infusion line. The device includes a catheter connecting piece or hub attachable at the puncture site on the skin surface of a patient, wherein the catheter hub has a connector for connecting the infusion line and an outlet for the flexible catheter tube; and a needle holder having a puncture needle (stylet), wherein the flexible catheter tube is arranged in the interior of the catheter hub and extends out of the outlet with an output end. The end of the flexible catheter tube opposing the output end is located in the interior of the catheter hub in the area of the connector and is separated from the surrounding area by a septum, wherein the needle holder securely fastens the puncture needle insertable into a passage channel of the catheter tube at the end opposing the pointed or sharp puncture tip. The needle holder is detachably arranged at the connector of the catheter hub in a starting position of the puncture device such that the puncture needle penetrates the septum and is guided in the passage channel of the catheter tube past the output end.
2. Description of Related Art
In medicine, catheters are used in various fields for administering drugs which have been dissolved or suspended in fluid. Using catheters medication can be directly administered into the patient's tissue or bloodstream via a puncture site. In order to attach the catheter it is necessary to create an entry into the tissue or bloodstream of the patient by means of a puncture. Various puncture devices are known for this purpose. Puncture devices of the type described above are especially intended for independent use by the patient, for example, for administering insulin with the aid of an insulin pump.
Aside from known puncture devices with a flexible catheter tube, other comparable products exist which feature a hollow needle made of steel or of a comparable metal rather than a tube with which medication is administered.
For puncture devices with a flexible catheter tube and a puncture needle, when the catheter hub is attached to the skin surface of the patient, the underlying tissue is pierced by the puncture needle, while the flexible catheter tube is inserted into the tissue in the process. The patient's stomach area is frequently chosen as the incision site for the puncture device. Following insertion, the puncture needle is withdrawn and removed. Only the catheter tube remains in the puncture site, wherein the catheter tube has previously been hooked up to an infusion line attached to the catheter hub and therefore, to medication delivery.
In a type of known puncture devices such as those described above, the outlet is located at the bottom side of the catheter hub which rests on the skin of the patient in the position of use, while an input end opposite the output end of the flexible catheter tube and the end thereof opposing the sharp or pointed tip of a puncture needle, extend out of the catheter hub at different openings. Both of these openings are sealed off by means of a septum with respect to the surrounding area.
A puncture device of the above-described type is distributed by the company Disetronic Medical Systems AG, in Burgdorf, Switzerland under the name “Disetronic®Tender”. The outlet for the flexible catheter tube in this puncture device is located at the side of the catheter hub. A hollow needle used as a puncture needle and securely fastened in a needle holder extends within the catheter tube which is guided through the interior of the catheter hub. The needle extends for the most part in a straight line and exits the catheter hub nearly horizontally at its side. For attaching the catheter, the patient—based on visual judgment—must first insert the puncture needle with the protruding end of the catheter tube at an angle of 30° to 45° into the skin, then pull the needle backwards out of the catheter tube, twist the catheter connector by 30° to 45° and finally secure it flatly to the skin. In doing so, the section of flexible catheter tube now located inside the body is also bent.
Although an additional septum is not necessary for this puncture device, the same problem arises as with puncture devices of the aforementioned type, namely that prior to insertion of such a puncture device the free volume of the catheter tube must either be vented or flooded with the medication to be administered. For this purpose, the hollow needle which is inserted into the septum and through to the output end of the catheter tube for creating a puncture must exhibit a laterally arranged vent hole or grinding, so that venting can be effected by way of the needle cavity or passageway. Since hollow needles are limited in minimal diameter by the fact that the needle cavity or passageway is passable by a fluid and the material surrounding the cavity is strong enough so as not to break, the minimal external diameter of the catheter tube is inevitably confined to a larger diameter than that of the guided hollow needle used for puncturing. Due to the subsequent, relatively large catheter tube size (in this case external diameters of 0.5 to 0.7 mm are common) the catheter tubes are perceived as uncomfortable or even painful by patients. Upon removal of the catheter, these puncture devices also leave behind wounds which are larger in diameter and thus, heal slower and are associated with a higher infection risk.
Consequently, the puncture devices of the aforementioned type are not as widely accepted by patients as desired or possible in spite of their otherwise existing advantages compared to puncture devices having a hard hollow needle made of metal (for example, no problems with nickel intolerance, no stiff needle which could cause pain when abutting the catheter). Moreover, the additional required step of venting makes attaching and handling the puncture device especially difficult for a patient when inserting it himself and gives way to risks caused by incorrect handling.
The puncture device known as Disetronic®Tender is especially complicated to handle (the angle choice) and there is a danger that incorrect operation or handling (a too large angle) can kink the output end of the catheter tube, thereby blocking the medication flow or even breaking the hollow needle used as a puncture needle in the body of the patient.